The objective of these studies is to extend our understanding of the mechanisms that control airway gland secretion. Two novel methods (monoclonal antibody production and cell isolation) for analysis of airway secretory function on a cell-specific basis are proposed. With these methods, secretion from serous, mucous and goblet cells will be monitored independently. The question, "What stimulates each cell?" can be asked. Stimulation-secretion coupling mechanisms can be defined for each cell type independently. In addition, the secretory product of each cell can be characterized independently. With this combined information, the physicochemical properties of mucus can be interpreted in comparison with the contribution of each cell type. The physicochemical properties of mucus may ultimately be controllable pharmacologically on the basis of information obtained through these studies. The proposed work will be extended from animals to humans. In addition, cell culture methods will be developed that will allow viable human tracheal epithelial and gland cells to be studied. Abnormalities in the function of human respiratory cells may be identified, potentially allowing medical therapy.